PCB (Printed Circuit Board) is also known as PWB Printed Wire Board.
A netlist indicates the connection relationship between the devices in the PCB or the schematic diagram.
The EDA technology enables a designer, by using a computer as a tool, to design a PCB on the EDA software platform based on the circuit schematic diagram, so as to achieve the functions as desired. The design of the printed circuit board mainly refers to the layout design, and it is necessary to consider the layout of external connections, the optimized layout of the internal electronic components, and the optimized layout of metal wiring and via holes and many other factors.
In an EDA software for the circuit design, both the schematic diagram and the PCB diagram have netlists. For example, in an EDA schematic diagram design software, pins of several devices are connected, and it is represented in the netlist as:
B3-IN2 L45-1 X6-3 C753-1
B3-IN2 is the network name after the pins are connected together. L45-1, X6-3 and C753-1 represent, respectively, pin 1 of the L45 component, pin 3 of the X6 component, and pin 1 of the C753 component. Typically, in a netlist, the network name of each connection relationship in the netlist portion of both the schematic diagram and the PCB should be the same. However, due to improper operation or conversion of different EDA software products, it may result in a situation that the network name may be changed while the connection relationship of the pins of the components remains unchanged. As shown below, the PCB netlist in an EDA LAYOUT wiring design software corresponds to the connection of certain pins of the devices in the above schematic diagram, and it is represented in the netlist as follows:
\TESTA\ \L45\-\1\ \X6\-\3\ \C753\-\1\
\TeSTA\ is the network name after the pins are connected together. \L45\-\1\, \X6\-\3\ and \C753\-\1\ represent, respectively, pin 1 of the L45 component, pin 3 of the X6 component, and pin 1 of the C753 component. Since the software systems have different requirements for the data format, there are some small differences in the format of the network name and the names of the pins in the PCB layout software, that is, the data is wrapped in “\”. However, after removing the “\”, the connection relationships are the same with the connection relationships of the component pins in the schematic diagram netlist, and only the first item, i.e., the network name, has changed (B3-IN2 is changed to TESTA).
Since the network connection relationship may be the same while the network name may have changed, it is difficult to compare whether the connection relationships contained in the PCB and the schematic diagram are consistent with each other after the schematic diagram design is completed. At this point, if the netlist of the schematic diagram is relocated back to the PCB, there may be a risk that the pins of some components are disconnected or new connections are added without prompt by the PBC software.